Accepting/declining pull request

Login to GitLab as tutorial_master. Go to Merge Requests tab(1) and open an interested pull request(2). Click Accept Merge Request(3). You can also decline(close) the pull request or return it with comment to developer by changing Assignee(4).

Configure GitLab credentials

Open Jenkins console and login as jenkins user. Go Credentials -> System -> Add domain (1,2,3). Enter tutorial-gitlab-credentials as Domain name(4) and click OK(5). Click Add Credentials on the next screen(6). Set tutorial_jenkins_master as Username(7), welcome1 as Password(8) and click OK (9).

Add another credentials to tutorial-gitlab-credentials domain(10). This time set Kind to Secret text(11) and paste your Private token into Secret(12). Enter PrivateToken_tutorial_jenkins_master as ID(13) and click OK(14).